In the left-hand pane, only the first image is loaded with the page. Each of the others (selectable from the pop-up list below the left-hand pane) must be loaded when called. After each one of these images loads, it is cached for instant access until you quit Navigator.
The idea here is that as long as the visitor is waiting for a page to load, all the images may as well be downloaded up front, allowing for instantaneous image access thereafter.
Activating the checkbox turns on a function that continually cycles through all pre-cached images at five-second intervals.
Scripting techniques of note: